Symbol rate detection of digitally modulated communication signals is used in many areas including synchronization, surveillance, identification and electronic intelligence gathering. Existing techniques include statistical moments, temporal correlation, spectral correlation, and instantaneous phase detection. These techniques have several drawbacks. The technique of statistical moments is complex and may not have the correct probability density function to model the signal. Temporal and spectral correlation result in output signals that contain periodic components with harmonics at multiples of the symbol rate and the carrier frequency, confusing the detection of the exact symbol rate. Instantaneous phase detection cannot detect exact symbol rate. All four techniques fail to detect the symbol rate for input signals with a small excess bandwidth factor.